In 2001, John Richards started the Apostrophe Protection Society, which aims to preserve the correct use of this much abused punctuation mark.
There's a Flickr group, called Grocer's Apostrophe which documents bad use of the punctuation mark at the grocery store, as well as several blogs like Apostrophe Catastrope and Apostrophe Abuse.
Whatever you do, just don't make mistakes with commas: an erroneous comma in a contract cost Rogers Communications $2 million!
More punctuation mark shenanigans at Miss Cellania.
I find that I just avoid apostrophes, and wind up with rather formal sounding language.